Apparatus for concentration of liquid solutions



D. J. STARK 2,865,920

N OF LIQUID SOLUTIONS APPARATUS FOR CONCENTRATIO Filed June 27, 1955 FIGJI bAvo J. STARK IN V EN TOR. WM

United States APPARATUS FOR ,CONCENTRATION OF LIQUID SOLUIIONS David `J. Stark, Tuscoia, lil., assignor to National Petro- Chemicals Corporation, New York, N. Y., a corporation of Delaware Application June 27,1955, Serial No. 517,977, 2 Claims. (Cl. 23-276) The present invention relates to a paratus for treatment of liqud solutions, such as aqueous solutions of mineral acds, and particularly for concentration in improved manner of aqueous solutions of mineral acids such as sulfurc acd.

tion (e. g., from about 60 to about 98% acd) in olefin hydration processes for production of alcohols wheren a the solution by evaporation of Water'therefrom. Generally, however, and in instances Wherein it is desired ditions of temperature, pressure, etc., in each stage being controlled depending upon the acd concentration of the solution treated therein and the extent of concentration t is desired to etfect in the particular stage. In conminimized fouling of the heating surfaces and minimized by-passing of the "heating surfaces by the acid solution being concentrated to obtair increased film heat transfer method and apincrease in film heat transfer coefiicient.

In accordance With this invention, concentration of a to the heating surfaces to be contacted by the liqud solution in each zone. More specifically, in accordance With the liqud to be concentrated is passed tion, and Figure II shows certain elements of the apparatus of Figure I to fa cilitate description thereo f.

lined With lead and refractory brick 2 is divided into a series of compartments 3, 4, 5 and 6 by vertical brick partitions 7, 8, 9 and 10, respectively, in a manner whereby partition 7 is common to compartments 3 and 4, partition 8 is common to compartments 4 and 5, partition 9 is common to compartments 5 and 6, and

partment 3, an opening 11 is provided for introduction into compartment 3 of liqud solution to be subjected to the heating surfaces in each compartment are maintained In the lower portion of eachof partitions 7, 8 and 9, a suitable opening 20, 21 and 22 respectively, is provided for passage of liqud from one .compartment to the succee ding compartment. In

Vessel 1 is'provided With a top 15 which is preferably' provided With a suitable opening or openings (not shown) for each of the compartments whereby Water evaporated in each compartment is withdrawn as vapor and, if de- Patetd Dec. 23, 1958.

means such as baffle elements 16,: 17 18 and 19 are: providedin. compar-tments 3, 4, artdfl respective1`y, in a' manner whereby liquid solution enteringr each Compartment through underflow openings. 20,; 21 and 22respectively, is subjected to change:in direction ofow whereby the liquid' solution flows upwardly to impinge upon the. heat transfer surfaces. To effectsuch aachange-of flow and provide the. improved results embodied herein, the bafile elements, which may be: composedlofi acidresistant brick, are rigidly. adhered. to. the bottomofi each compartment and each baffie,.with-, respect to, its surface area facing the particular acidinlet whichittaccommodates, is sufiiciently larger than the diameter' of the inlet and is so disposed with respectvto the. inlet that all, or substantially. all of the liquid solution. passing through the inlet is subjecte'dto change. of directional' flow by the, baffie element whereby. the. liquid solution-mpinges on heat surfaces disposed in the particular compartment. In-

preferred aspect, the bafie means in each compartment extends from the outer wall of the. compartment to, a point past the acid inlet to the compartment` as is shown in Figure I; and, as also shown, each bale is preferably substantially parallel to the partition containing the particular acid inlet which the hafe aecornmodates. Although such disposition of the baie elements With respect to the partition openings which they accommodate represents a preferred embodiment, it should be understood that other than a substantially arallel arrangement may be employed as long as the arrangement provides the change of directonal flow adequate for providing the improved' results embodied'by the nvention.

In practice. of. the. invention as embodied herein and' with use of an apparatus as illustrated lIL the drawing, liquid. solution to be concentrated is passed, into compartment 3 via opening 11 at a defined velocity, cor r'elatedf with the rate of withdrawal from overfiow opening 12.2 incompartment 6 and the liquid evaporated and removed as vapor from each compartment,.such that in each: compartment the liquid level is maintained below the top of each compartment but above. the heating surfaces-in each compartment. By disposition of bale means adjacent to the inlet to each compartment as shown to direct flow of liquid into contact with the heating surfaces, by-passing of the heat surtaces is avoided in apparatus of the underow type as aforedescribed. Since. the acid solution is introduced at a relatively high feed rate into an apparatus of the type described and flow of solution into each compartment is directed to the outlet from each compartment, in absence of the described bafile elements the solution tends to by-pass the heat transfer surfaces, thereby flowing through the concentrator with little or no concentration of the by-passng acd, resulting in introductio-n into a succeeding. compartment of acid that has not undergone substantial, if any, concentration in the preceding compartment. By use of the bathe means specially disposed with respect to the acid inlets and heatingsurfaces in each compartment, by-passing is avoided, increased acid fiow past the heat transfer surfaces occurs resulting in reduced fouling of heat transfer surfaces, and a substantial increase in film -heat transfer coelficient is obtained.

In a specific embodiment, the invention was carried out using an apparatus, as illustrated in Figure I, in which vessel 1 was a cylindrical tank, as aforedescribed, 23' 8" in height and 15' 2" in diameter. The tank was partitioned into four compartments by means of Vertical brick partitions 7, 8, 9 and 10 with partitions 7, 8` and 9 each having an opening (6", I. D.) in the lower portion of each partition. Acid inlet 11, also 6", I. D., was pro-` vided in` the outer wall of compartment 3 at a' lower portion of said wall and, in the outer wall of Compartment 6, ar over-flow outlet (6", I. D.) was provided at an elevation such that a liquid level of 5' 10" was maintained in compartment 6, whereby the surface level of liquid in each of the series of compartments was at an elevation suflicient to maintain the heating surfaces (banks. of steam torpedo tubes) in each compartment immersed in liquid solution undergoing concentration. By opera-- tion of the apparatus for concentration of aqueous solutions of" from about78 to -1% acid strength. to solutions of about 84% acidg an-averageincrease of 102% in heat transfer coefficientwasobtained by provision in the'` apparatus of bathe elementszl, 17, 18 and 19 -in the manncr described hereinbefore and illustrated in the drawings, thus illustrating the. improvement resulting from practice of' the inventionin' which the acid solution introduced into each of theseries of compartments is controlled with respect to direction of flow so as to impinge on heat transfer surfaces in the compartments and minimize undesirable by-passing; ofi the heat surtaces by liquid solutionundergoingconcentration;

While there are= above disclosed` but a limited number possible to produce still otherembodiments without departing from theinventive concept herein disclosed, and

it is-desired therefore that only such limitations be irnposed` onthe appcnded claims asi are stated therein.

What is claimed: isi 1. Anapparatus, adapted for concentration of liquid' solutions, comprising a. vertically elongated vessel vertically partitioned into a plurality of compartments,a heatingsurface. ineach' of: said compartments, said heating surface being; positioned at an elevation above the bottom butbelow: the'top r of the compartment, inlet meansin the: firstof said` compartments for introduction of liquidzlinto a: lower portion of; said; first compartment, means inthe. lower. portionofi all but the last ot said. compartments. for passage' ot'liquidfrom each compartment outlet means: in thelast of said compartments for withdrawal of' liquid'` from' said last compartment, said outlet means being. positioned atan elevation above the heating surface in said last compartment, and bathe means inz each of said compartments positioned with respect to` the' inlet means: to each. compartment to direct liquid introduced into each compartment into contact With the heating surface. in' that compartment.

2. An apparatus, adapted for concentration of liquid solutions, comprising a cylindrical vessel vertically partitioned into a plurality of compartments, each of which compartments contains a heating surface positioned at an=e1evation abovethe bottom oli each compartment but below. the top of each compartment, inlet means in the first of said compartments for` the introduction of liquid into a lower portion of said first compartment, means in the lower portion ofall butthe last of said compartments for passage of liquid from each compartment to its succeeding compartment, outlet means in the last of said compartments for withdrawal of liquid from said last compartment, said outlet means being positioned at an elevation above* the heating surface in said last Compartment, and bathe-'means in each of said compartments positioned Withrespect to the inlet means in each compartment to direct liquid introduced into eachcompartment into contact with the heating surface in each Compartment.

References cited in the file of this patent 4 UNITED .STATES PATENTS in W... 

1. AN APPARATUS, ADAPTED FOR CONCENTRATION OF LIQUID SOLUTIONS, COMPRISING A VERTICALLY ELONGATED VESSEL VERTICALLY PARTITIONED INTO A PLURALITY OF COMPARTMENTS, A HEATING SURFACE IN EACH OF SAID COMPARTMENTS, SAID HEATING SURFACE BEING POSITIONED AT AN ELEVATION ABOVE THE BOTTOM BUT BELOW THE TOP OF THE COMPARTMENT, INLET MEANS IN THE FIRST OF SAID COMPARTMENTS FOR INTRODUCTION OF LIQUID INTO A LOWER PORTION OF SAID FIRST COMPARTMENT, MEANS IN THE LOWER PORTION OF ALL BUT THE LAST OF SAID COMPARTMENTS FOR PASSAGE OF LIQUID FROM EACH COMPARTMENT, OUTLET MEANS IN THE LAST OF SAID COMPARTMENTS FOR WITHDRAWAL OF LIQUID FROM SAID LAST COMPARTMENT, SAID OUTLET MEANS BEING POSITIONED AT AN ELEVATION ABOVE THE HEATING SURFACE IN SAID LAST COMPARTMENT, AND BAFFLE MEANS IN EACH OF SAID COMPARTMENTS POSITIONED WITH RESPECT TO THE INLET MEANS TO EACH COMPARTMENT TO DIRECT LIQUID INTRODUCED INTO EACH COMPARTMENT INTO CONTACT WITH THE HEATING SURFACE IN THAT COMPARTMENT. 